Chlorine-doped CdS thin films from CdCl2-mixed CdS powder

Abstract

The CdS:Cl thin films have been prepared using thermally evaporated, CdCl 2 -mixed CdS powder at 200°C substrate temperature. The percentage of CdCl 2 in the mixture varied from 0% to 0.20%. The electrical properties and the grain size of the deposited films were investigated. The results show that light doping, resistivity, carrier concentration, and mobility follow Seto's model for polycrystalline material. However, with heavy doping, these properties undergo a saturation trend. The saturation behavior can be understood in terms of the rapid formation of the A-center complexes in the films. The deposited films were annealed at 250°C and 300°C.The resistivity of pure and lightly doped CdS films increased with annealing temperature, whereas carrier concentration and mobility in these films decreased. However, for the higher doping concentrations, the resistivity decreased, whereas carrier concentration and mobility showed improvement. These changes in electrical properties of the deposited films with annealing and doping concentration are attributed to a reduction in the lattice defect sites in CdS upon annealing. The experimental results are interpreted in terms of a modified version of Seto's model for polycrystalline materials.

Comparative Studies on Temperature Dependent I–V Characteristics of Al∕(p)CdTe and Ni∕(n)CdS Schottky Junctions and Their PV Effect

“…CdS thin films have been obtained by several methods, such as electro-deposition, vacuu evaporation, screen-printing, photochemical deposition, closed bath deposition (CBD), spray pyrolysis and sputtering. Many researchers have focused their work on the enhancement of the electrical and optical properties of pure and doped CdS films to produce high efficiency solar cells [8].…”

Doping of CdS nanoparticles

“…Suitable CdS films can be produced by annealing a mixture of CdS and CdCl 2 micron/submicron sized powders at high temperatures in the range of 550-690 • C or by postdeposition annealing treatment at 250-450 • C of CdS thin films, deposited by thermal evaporation, spray pyrolysis and chemical bath deposition (CBD) methods [2][3][4]. This process leads to recrystallization of the CdS layer, decrease of crystallite boundaries, sintering of CdS particles and doping of the CdS material by chloride anions.…”

Structural studies on some doped CdS thin films deposited by thermal evaporation

“…Ternary chalcogenide systems are known to have welldefined band structure in which the energy gap vary continuously with composition between their values in the constituent compounds [9][10][11]. Such materials allow the possibility of tailoring their properties to meet specific requirements.…”